Along with great development of electronic engineering and communication engineering, a mobile communication terminal is recently provided with various functions. That is, as techniques related to wireless communication and data processing have been rapidly developed, persons may use various functions such as Internet accessing, image communication and moving picture transmission as well as voice call using a mobile communication terminal. In addition, due to rapid propagation of the mobile communication terminals, mobile communication terminals cover a numerous amount of communications among persons, and thus mobile communication terminals become an essential communication means in the present days.
Among various functions of such a mobile communication terminal, SMS (Short Message Service) or voice message service capable of rapidly sending simple information to an opponent is widely used. The SMS allows a person to rapidly and conveniently send desired information to one or many opponent(s) at a very lower cost than a voice call, and also the received text message may be stored for checking it again in the future. Owing to such advantages, the SMS is widely used for providing payment information (price, product details, account information and so on) in an electronic payment service.
An existing SMS just functions to code and send a text. However, users of mobile communication terminals desire to process the content of a message in more various ways. That is to say, there are more needs to enhance decoration of a text message by adding visual or auditory effects such as emoticons, images, moving pictures and sounds, in addition to sending a simple message purpose.
In order to meet such needs of the users, there have been proposed various techniques for converting a short message into a multimedia message by changing a typing style, size or color of SMS or adding images such as avatar, graphic emoticons, moving pictures and sounds thereto.
Korean Laid-open Patent Publication No. 2002-11033 (hereinafter, referred to as '033 patent) discloses a method in which, if a subscriber sends multimedia event index information to a SMS center in a mobile communication network together with a short message, the SMS center determines whether a multimedia event data corresponding to the index exists in a receiving terminal, and then provides the multimedia index information to the receiving terminal together with the short message if it exists in the receiving terminal, so that a multimedia event such as a moving picture and a sound is generated in the receiving terminal.
In addition, Korean Laid-open Patent Publication No. 2004-25438 (hereinafter, referred to as '438 patent) discloses a method for changing a graphic emoticon included in a message into a mapped text when a text message is transmitted, and analyzing a received text message so that a text corresponding to the graphic emoticon is changed into a mapped graphic emoticon and then displayed.
In case of the '033 patent and the '438 patent, it is required to store a separate program or data in a sending/receiving terminal so as to convert a short message into a multimedia message.
Korean Laid-open Patent Publication No. 2004-86963 (hereinafter, referred to as '963 patent) discloses a SMS service method for providing a callback URL (Uniform Resource Locator) capable of downloading an avatar image to a receiving terminal together with a short message.
In addition, Korean Laid-open Patent Publication No. 2001-16442, Korean Laid-open Patent Publication No. 2003-35249 and Korean Laid-open Patent Publication No. 2004-100700 disclose a method in which, if a sending subscriber transmits conversion request information (e.g., special key, conversion command, and text image information) together with a text message data, a text message processing means of the mobile communication network converts the short message into a multimedia message based on the conversion request information of the user and then provides the multimedia message to a receiving terminal.
However, in order to include separate conversion request information in a short message sent to the mobile communication network as mentioned above, a dedicated program should be installed in a sending terminal, or a separate user action for inputting the conversion request information is required.
In addition, for a PCX/MSC (Personal Communication eXchange/Mobile Switching Center) or SMSC (Short Message Service Center) of a mobile communication network to recognize the conversion request information sent from a sending terminal, it is required to change an existing protocol or correct an operating program of the PCX/MSC or the SMSC.
Thus, there is still a need for a short message converting method, which does not request any upgrading of a sending/receiving terminal, additional action of a user, or any change of the mobile communication network.